# job_queue_shim.py
# Description: Temporary job queue implementation for Chatbook module
#
"""
Job Queue Shim for Chatbook Operations
--------------------------------------

FIXME: This is a TEMPORARY implementation to provide job queue functionality
for the Chatbook module. This should be replaced with the centralized job
queue module once it's available.

TODO: Replace this entire module with calls to the centralized job queue service.

This shim provides:
- Basic job enqueuing and status tracking
- Simple async job processing
- Database-backed persistence
- Compatible interface for future replacement
"""

import asyncio
import json
import uuid
from datetime import datetime, timedelta
from typing import Dict, Any, Optional, List, Callable, Union
from enum import Enum
from dataclasses import dataclass, asdict
from pathlib import Path
from loguru import logger


class JobStatus(str, Enum):
    """Job status enumeration."""
    PENDING = "pending"
    QUEUED = "queued"
    IN_PROGRESS = "in_progress"
    COMPLETED = "completed"
    FAILED = "failed"
    CANCELLED = "cancelled"
    EXPIRED = "expired"


class JobType(str, Enum):
    """Job type enumeration."""
    EXPORT_CHATBOOK = "export_chatbook"
    IMPORT_CHATBOOK = "import_chatbook"
    VALIDATE_CHATBOOK = "validate_chatbook"
    CLEANUP_EXPIRED = "cleanup_expired"


@dataclass
class Job:
    """Job data structure."""
    job_id: str
    job_type: JobType
    status: JobStatus
    user_id: str
    payload: Dict[str, Any]
    created_at: datetime
    started_at: Optional[datetime] = None
    completed_at: Optional[datetime] = None
    expires_at: Optional[datetime] = None
    error_message: Optional[str] = None
    result: Optional[Dict[str, Any]] = None
    progress: int = 0
    max_retries: int = 3
    retry_count: int = 0
    metadata: Dict[str, Any] = None

    def to_dict(self) -> Dict[str, Any]:
        """Convert job to dictionary."""
        data = asdict(self)
        # Convert datetime objects to ISO format strings
        for key in ['created_at', 'started_at', 'completed_at', 'expires_at']:
            if data.get(key):
                data[key] = data[key].isoformat() if hasattr(data[key], 'isoformat') else data[key]
        # Convert enums to strings
        data['job_type'] = str(self.job_type.value) if isinstance(self.job_type, Enum) else str(self.job_type)
        data['status'] = str(self.status.value) if isinstance(self.status, Enum) else str(self.status)
        return data

    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> 'Job':
        """Create Job from dictionary."""
        # Convert string dates back to datetime
        for key in ['created_at', 'started_at', 'completed_at', 'expires_at']:
            if data.get(key) and isinstance(data[key], str):
                data[key] = datetime.fromisoformat(data[key])
        # Convert string enums back to enums
        if 'job_type' in data:
            data['job_type'] = JobType(data['job_type'])
        if 'status' in data:
            data['status'] = JobStatus(data['status'])
        return cls(**data)


class JobQueueShim:
    """
    Temporary job queue implementation.

    FIXME: Replace this with centralized job queue service when available.
    This is a stopgap solution to provide async job processing for Chatbooks.
    """

    def __init__(self, db_connection=None):
        """
        Initialize job queue shim.

        Args:
            db_connection: Database connection for job persistence
        """
        self.db = db_connection
        self._jobs: Dict[str, Job] = {}
        self._handlers: Dict[JobType, Callable] = {}
        self._processing_task = None
        self._is_running = False
        self._processing_lock = asyncio.Lock()

        # FIXME: This in-memory storage is not suitable for production
        # Should be replaced with proper queue backend (Redis, RabbitMQ, etc.)
        logger.warning("JobQueueShim initialized - THIS IS A TEMPORARY IMPLEMENTATION")

    def register_handler(self, job_type: JobType, handler: Callable):
        """
        Register a handler for a job type.

        FIXME: Handler registration should be managed by centralized service.

        Args:
            job_type: Type of job to handle
            handler: Async function to process the job
        """
        self._handlers[job_type] = handler
        logger.info(f"Registered handler for {job_type.value}")

    async def enqueue_job(
        self,
        job_type: JobType,
        user_id: str,
        payload: Dict[str, Any],
        expires_in: Optional[timedelta] = None,
        metadata: Optional[Dict[str, Any]] = None
    ) -> str:
        """
        Add a job to the queue.

        FIXME: Should call centralized job queue service's enqueue method.

        Args:
            job_type: Type of job
            user_id: User who created the job
            payload: Job data
            expires_in: Time until job expires
            metadata: Additional metadata

        Returns:
            Job ID
        """
        job_id = str(uuid.uuid4())

        job = Job(
            job_id=job_id,
            job_type=job_type,
            status=JobStatus.PENDING,
            user_id=user_id,
            payload=payload,
            created_at=datetime.utcnow(),
            expires_at=datetime.utcnow() + expires_in if expires_in else None,
            metadata=metadata or {}
        )

        # Store in memory (FIXME: Use proper storage)
        self._jobs[job_id] = job

        # Persist to database if available
        if self.db:
            await self._persist_job(job)

        # Start processing if not already running
        if not self._is_running:
            self._processing_task = asyncio.create_task(self._process_queue())

        logger.info(f"Enqueued job {job_id} of type {job_type.value} for user {user_id}")
        return job_id

    async def get_job(self, job_id: str, user_id: Optional[str] = None) -> Optional[Job]:
        """
        Get job by ID.

        FIXME: Should query centralized job storage.

        Args:
            job_id: Job ID
            user_id: Optional user ID for access control

        Returns:
            Job if found and accessible
        """
        # Try memory first
        job = self._jobs.get(job_id)

        # Try database if not in memory
        if not job and self.db:
            job = await self._load_job(job_id)

        # Check user access
        if job and user_id and job.user_id != user_id:
            logger.warning(f"User {user_id} attempted to access job {job_id} owned by {job.user_id}")
            return None

        return job

    async def update_job_status(
        self,
        job_id: str,
        status: JobStatus,
        error_message: Optional[str] = None,
        result: Optional[Dict[str, Any]] = None,
        progress: Optional[int] = None
    ):
        """
        Update job status.

        FIXME: Should call centralized job queue's status update.

        Args:
            job_id: Job ID
            status: New status
            error_message: Error message if failed
            result: Job result if completed
            progress: Progress percentage
        """
        job = await self.get_job(job_id)
        if not job:
            logger.error(f"Job {job_id} not found for status update")
            return

        job.status = status

        if status == JobStatus.IN_PROGRESS and not job.started_at:
            job.started_at = datetime.utcnow()
        elif status in [JobStatus.COMPLETED, JobStatus.FAILED, JobStatus.CANCELLED]:
            job.completed_at = datetime.utcnow()

        if error_message:
            job.error_message = error_message
        if result:
            job.result = result
        if progress is not None:
            job.progress = progress

        # Update in memory
        self._jobs[job_id] = job

        # Persist to database
        if self.db:
            await self._persist_job(job)

        logger.info(f"Updated job {job_id} status to {status.value}")

    async def cancel_job(self, job_id: str, user_id: Optional[str] = None) -> bool:
        """
        Cancel a job.

        FIXME: Should call centralized job queue's cancel method.

        Args:
            job_id: Job ID
            user_id: User requesting cancellation

        Returns:
            True if cancelled successfully
        """
        job = await self.get_job(job_id, user_id)
        if not job:
            return False

        if job.status in [JobStatus.COMPLETED, JobStatus.FAILED, JobStatus.CANCELLED]:
            logger.warning(f"Cannot cancel job {job_id} in status {job.status.value}")
            return False

        await self.update_job_status(job_id, JobStatus.CANCELLED)
        return True

    async def list_jobs(
        self,
        user_id: Optional[str] = None,
        job_type: Optional[JobType] = None,
        status: Optional[JobStatus] = None,
        limit: int = 100,
        offset: int = 0
    ) -> List[Job]:
        """
        List jobs with filters.

        FIXME: Should query centralized job storage.

        Args:
            user_id: Filter by user
            job_type: Filter by type
            status: Filter by status
            limit: Maximum results
            offset: Skip results

        Returns:
            List of matching jobs
        """
        jobs = list(self._jobs.values())

        # Apply filters
        if user_id:
            jobs = [j for j in jobs if j.user_id == user_id]
        if job_type:
            jobs = [j for j in jobs if j.job_type == job_type]
        if status:
            jobs = [j for j in jobs if j.status == status]

        # Sort by creation time (newest first)
        jobs.sort(key=lambda j: j.created_at, reverse=True)

        # Apply pagination
        return jobs[offset:offset + limit]

    async def cleanup_expired_jobs(self) -> int:
        """
        Remove expired jobs.

        FIXME: Should be handled by centralized job queue maintenance.

        Returns:
            Number of jobs cleaned up
        """
        now = datetime.utcnow()
        expired_jobs = [
            job_id for job_id, job in self._jobs.items()
            if job.expires_at and job.expires_at < now
        ]

        for job_id in expired_jobs:
            await self.update_job_status(job_id, JobStatus.EXPIRED)
            del self._jobs[job_id]

        if expired_jobs:
            logger.info(f"Cleaned up {len(expired_jobs)} expired jobs")

        return len(expired_jobs)

    async def _process_queue(self):
        """
        Process jobs in the queue.

        FIXME: This is a very basic implementation. The centralized service
        should provide proper queue processing with priorities, retries, etc.
        """
        self._is_running = True
        logger.info("Job queue processing started")

        try:
            while self._is_running:
                async with self._processing_lock:
                    # Find pending jobs
                    pending_jobs = [
                        job for job in self._jobs.values()
                        if job.status == JobStatus.PENDING
                    ]

                    for job in pending_jobs:
                        # Check if handler exists
                        handler = self._handlers.get(job.job_type)
                        if not handler:
                            logger.error(f"No handler for job type {job.job_type.value}")
                            await self.update_job_status(
                                job.job_id,
                                JobStatus.FAILED,
                                error_message=f"No handler for job type {job.job_type.value}"
                            )
                            continue

                        # Process job
                        try:
                            await self.update_job_status(job.job_id, JobStatus.IN_PROGRESS)

                            # Execute handler
                            result = await handler(job)

                            await self.update_job_status(
                                job.job_id,
                                JobStatus.COMPLETED,
                                result=result
                            )
                        except Exception as e:
                            logger.error(f"Error processing job {job.job_id}: {e}")

                            # Handle retries
                            job.retry_count += 1
                            if job.retry_count < job.max_retries:
                                job.status = JobStatus.PENDING
                                logger.info(f"Retrying job {job.job_id} ({job.retry_count}/{job.max_retries})")
                            else:
                                await self.update_job_status(
                                    job.job_id,
                                    JobStatus.FAILED,
                                    error_message=str(e)
                                )

                # Cleanup expired jobs periodically
                await self.cleanup_expired_jobs()

                # Sleep before next iteration
                await asyncio.sleep(1)

        except Exception as e:
            logger.error(f"Queue processing error: {e}")
        finally:
            self._is_running = False
            logger.info("Job queue processing stopped")

    async def stop(self):
        """Stop queue processing."""
        self._is_running = False
        if self._processing_task:
            await self._processing_task

    async def _persist_job(self, job: Job):
        """
        Persist job to database.

        FIXME: This should use the centralized job storage.
        """
        if not self.db:
            return

        try:
            # Store as JSON in a generic job table
            # This is a simplified implementation
            job_data = json.dumps(job.to_dict())

            # TODO: Implement actual database persistence
            # For now, just log
            logger.debug(f"Would persist job {job.job_id} to database")
        except Exception as e:
            logger.error(f"Error persisting job {job.job_id}: {e}")

    async def _load_job(self, job_id: str) -> Optional[Job]:
        """
        Load job from database.

        FIXME: This should query the centralized job storage.
        """
        if not self.db:
            return None

        try:
            # TODO: Implement actual database loading
            # For now, return None
            logger.debug(f"Would load job {job_id} from database")
            return None
        except Exception as e:
            logger.error(f"Error loading job {job_id}: {e}")
            return None


# FIXME: Global instance for convenience - should be replaced with proper DI
_global_queue: Optional[JobQueueShim] = None


def get_job_queue() -> JobQueueShim:
    """
    Get the global job queue instance.

    FIXME: This global pattern should be replaced with proper dependency injection
    when integrating with the centralized job queue service.
    """
    global _global_queue
    if not _global_queue:
        _global_queue = JobQueueShim()
    return _global_queue


async def cleanup_module():
    """
    Cleanup module resources.

    FIXME: Should be handled by centralized service lifecycle.
    """
    global _global_queue
    if _global_queue:
        await _global_queue.stop()
        _global_queue = None
